This invention relates generally to lithotriptor devices, and more particularly, to audible noise emissions from acoustic shock wave generators of such devices.
Lithotriptors are devices employed in medical and therapeutic extracorporeal treatment of humans and animals for the destruction of concretions (e.g. kidney stones), induction of bone growth, and treatment of other soft-tissues. These devices operate by producing focused acoustic shock waves capable of creating extremely high pressure differentials at localized regions within a patient's body that act upon targeted concretions or bodily tissue being treated.
Various types of lithotriptors utilize different means for producing acoustic shock waves. Such means are known in the art and include electromagnetic, piezoelectric, and electrical spark-gap generators. While the type of generator used to produce the acoustic shock waves varies from one lithotriptor to the next, each type of generator ultimately produces acoustic shock waves capable of being focused in a specific trajectory and at a certain depth.
Because the focal point or isocenter of a conventional shock wave generator is fixed, the generator of a conventional lithotriptor is typically encased in a housing suspended from a moveable arm such that the trajectory of the acoustic shock waves can be aligned relative to a patient receiving treatment. While the movable arm of the lithotriptor allows alignment of the shock wave trajectory, the depth of the shock wave within the patient's body is controlled by expansion and contraction of a fluid-filled cushion that extends through the housing and engages the patient's epidermis.
In addition to the arm and fluid-filled cushion extending from the generator housing, conventional lithotriptors may include a fluid supply line or hose extending from the housing to provide means for liquid cooling of the generator. Furthermore, the housing may have one or more mechanisms for aligning the isocenter of the acoustic shock waves relative to the patient.
Although lithotriptor devices have proven useful in medical treatment and therapy, such devices produce a significant amount of unfocused noise when generating the acoustic shock waves. Such noise results from the discharge of capacitors, generation of sparks, or other means used to create the acoustic shock waves.
In addition to disturbing those present in a room in which the device is being used, the audible noise emissions of the lithotriptors have been known to distract and disturb persons in adjacent or nearby rooms. This is especially problematic in modern operating rooms that often share a common sterile hallway with little or no means of preventing sound transfer between adjacent rooms. In such situations, noise generated by use of lithotriptor can disturb medical personnel performing intricate surgery in adjacent rooms.